Heart valve disease, and particularly aortic heart valve disease, is a medical problem afflicting many individuals throughout the world. Over time, natural heart valves may leak causing aortic insufficiency or regurgitation. They may also become blocked or exhibit limited function due to aortic stenosis. Among the treatment options for either condition is the destruction of the native valve and insertion of a prosthetic valve through a transapical approach using a minimally invasive delivery device.
Prosthetic valves may be formed from biological materials such as harvested bovine valves or pericardium tissue. Such valves are typically fitted within, and form a portion of, a biologically compatible stent, which may be inserted into the heart at the annulus of the compromised native valve to replace the native valve. For such insertion, it is often necessary to compress the stent to a reduced diameter for loading onto the delivery device and for insertion into the body, whereupon it may be expanded.
In the case of valves formed with biological materials, the stented valve is preferably preserved in the open condition for storage as compression of the valve material for extended periods compromises the integrity of the biological valve. It is therefore necessary to crimp the valve, or reduce its diameter for use in the insertion device, in the operating arena.